This invention relates to optical fiber waveguides and, more particularly, to the coupling of light power from semiconductor light sources to optical fiber waveguides and to the coupling of light power from optical fiber waveguides to semiconductor optical detectors.
Optical fiber waveguides are likely to find increased use as the medium for the transmission of information signals because of their large signal carrying capabilities. In optical transmission systems, analog or digital information signals modulate the light output of a semiconductor source, such as a laser or a light-emitting diode (LED) and the modulated light power is coupled to the optical fiber waveguide.
In the prior art, coupling between a light-emitting diode and an optical fiber is structurally arranged by disposing the optical fiber on or near the light-emitting area of the light source, such that the central axis of the fiber is perpendicular to the emitting area. This structural arrangement, however, has manufacturing disadvantages. For example, an electrical-to-optical converter will include a ceramic substrate upon which is mounted a light-emitting diode connected to an optical fiber waveguide and an integrated circuit (IC) for driving the LED. When the LED is mounted so that its light-emitting area is parallel to the plane of the substrate, the optical fiber emerges perpendicular to the plane of the substrate which is a disadvantageous arrangement for manufacturing purposes. Alternatively, if the optical fiber waveguide is mounted parallel to the substrate, the LED is mounted perpendicular to the plane of the ceramic substrate. Neither of these prior art arrangements readily lends itself to a compact structural package. In addition, the prior art coupling arrangement lacks strength, since contact between the fiber and LED occurs only at the end of the fiber. Similar structural problems exist in the prior art coupling arrangements between optical fiber waveguides and semiconductor optical detectors.
An object of the present invention is to couple light power from a semiconductor light source into an optical fiber waveguide.
An additional object of the present invention is to couple light power from an optical fiber waveguide into a semi-conductor optical detector.